CVE-2025-47170: Use After Free Vulnerability in Microsoft Office Word

Overview

The cybersecurity community is buzzing with discussions around a newly discovered vulnerability designated as CVE-2025-47170. This vulnerability, found in Microsoft Office Word, is of particular concern as it allows an unauthorized attacker to execute code locally, potentially leading to a system compromise or data leakage. Given the widespread usage of Microsoft Office Word, this vulnerability has a vast potential impact, affecting millions of users, businesses, and organizations worldwide.
The gravity of this vulnerability is further underscored by its high CVSS (Common Vulnerability Scoring System) score of 7.8, indicating it to be a major threat that requires prompt attention. In this blog post, we delve deeper into the inner workings of this vulnerability, its potential impacts, and how it can be mitigated.

Vulnerability Summary

CVE ID: CVE-2025-47170
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office Word | All versions prior to the patch

How the Exploit Works

The vulnerability lies in the handling of memory objects within Microsoft Word. A flaw in the programming allows for the possibility of a “use after free” condition. This means that an attacker can manipulate an application to use memory after it has been freed or deleted, leading to arbitrary code execution.
The attacker would need to craft a malicious Microsoft Word document and get the user to open it. Upon opening the document, the malicious code embedded within it would execute, potentially compromising the user’s system or leading to data leakage.

Conceptual Example Code

Here is a conceptual example of how the vulnerability might be exploited. This pseudocode is meant to illustrate the vulnerability, not provide an actual exploit.

// Craft malicious document
maliciousDoc = createWordDocument();
embedMaliciousCode(maliciousDoc, "...");
// Send to victim
sendToVictim(maliciousDoc, victimEmail);
// Wait for victim to open document
waitForOpen(maliciousDoc);
// Execute code upon document open
executeCode(maliciousDoc);

This exploit hinges on the victim opening the malicious document. As such, it is crucial for users to be wary of opening documents from untrusted sources. It’s also important for system administrators and cybersecurity personnel to apply the vendor patch as soon as possible to mitigate this vulnerability. If immediate patching is not possible, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation.